1. Field of the Invention
The present invention relates to a rotor structure for a motor and, more particularly, to a rotor structure that includes fixing seats securely coupling a shaft and a magnet together.
2. Description of the Related Art
As shown in FIG. 1, a conventional rotor structure for a brushless motor includes a shaft 10 and a magnet 20. The magnet 20 is in a shape of a cylinder with an axial hole 21 extending through the magnet 20 along a centerline of the cylinder for the shaft 10 to pass through said axial hole 21. Conventionally, there are two ways to provide a linkage between the shaft 10 and the magnet 20, which are linkages realized through “tight-fit design” or through “adhesive” and are discussed in detail as follow.
The linkage between the shaft 10 and magnet 20 provided by “tight-fit design” is achieved by arranging the axial hole 21 of the magnet 20 tightly fitting the shaft 10, in a way such that the magnet 20 is coupled with the shaft 10 and able to synchronously revolve therewith. However, owing to the fragility of the magnet 20, coupling the shaft 10 and the magnet 20 by “tight-fit design” leads the magnet 20 to rupture easily. Moreover, if the magnet 20 does not fit the shaft 10 tightly enough, the shaft 10 may be disengaged from the magnet 20 due to temperature-induced expansion and contraction. Also, disengagement between the shaft 10 and the magnet 20 will further cause the magnet 20 to be unable to synchronously revolve with the shaft 10.
Linking the shaft 10 and the magnet 20 through “adhesive” is achieved by applying adhesive between the shaft 10 and the axial hole 21 of the magnet 20, such that the magnet 20 is coupled with the shaft 10 and able to synchronously revolve therewith. However, the lifetime of the applied adhesive is limited, which will not be able to provide stickiness when the lifetime thereof is ended. Besides, since the rotor structure is ordinarily operated under high temperature and high rotational speed, the lifetime of said adhesive is easily shortened.
Accordingly, there is a need for redesigning the conventional rotor structure.